CHAPTER 4 IMAGE FORMATION SYSTEMCOPYRIGHT © 1999 CANON INC. CANON NP6317 REV.0 APR. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)4-4B. Mechanism1. Turning the Scanning Lamp ON and OFFThe microprocessor (Q300) on the DC controller PCB controls the lamp regulator. The scan-ning lamp goes ON when the scanning LAMP ON command (LOAN) is '1', and it goes OFF whenthe signal is '0'.2. Controlling the Intensity of the Scanning LampThe intensity of the scanning lamp is controlled by the lamp shift signal.The intensity of the scanning lamp is changed.When the reproduction ratio is different than 100% changing the T-on time of the lamp shiftsignal. The T-on time of the lamp shift signals is fixed to 5ms at 100%. During AE exposure,however, the voltage (135 V) applied to the scanning lamp remains the same.The adjusts the copy density using its development bias; see p. 10-18.3. Error ProtectionThe condition of the scanning lamp is monitored using the lamp check signal.If the lamp check signal is received by the DC controller even when the lamp is off, the errordetection circuit generates the AC SHUTOFF signal to force the relay (K100) on the AC driver/DCpower supply PCB to go OFF, thereby cutting AC power supply (p. 3-39). In this case, E220 erroris displayed.4. Zero-Cross SignalThe board generates the zero cross signal that the DC controller uses to control the fixingheater temperature. E261 is indicated on the control panel if an zero cross error is identified.Figure 4-201Microprocessor (Q300)Transistor(Q320)ErrordetectioncircuitDC controller PCB Lamp driver unitTriac-triggering circuitFU2Scanning lamp(LA1)J202-3J202-1IntensityswitchingcircuitLamp ONdetectioncircuitPhasecontrolswitchingcircuitJ306MEATLAMPCHECKLAMP-ONZEROCROSSLAMPSHIFT-4J305-3 J203J203-5-4J305-1J305-2J203-6J305-4 J203-3-1-2J201K100RelayShort connectorPower supply assembly
